Origin-destination matrix are an important tool in urban transportations planning, but it is too expensive to get a well-done one every year (at least in a city like São Paulo Metropolitan Region with more han 20million people). Cars with RFID and sensors spread out the whole city would help understanding the travel behavior of car drivers. Similarly, this ideia could be apllied to people and in both cases it is highly recommended to engage a ​​prior discussion about data privacy.